Stable Coil Research Articles

Superconducting field coil for high-voltage homopolar generator

A homopolar generator with 500 volts output is being designed and built as a pulsed power source. A key component used in achieving this high output voltage is the 5 tesla field coil. A superconducting coil is required for a compact configuration that operates above the saturation of iron. The coil case is 158 cm long and has an outside diameter of 137 cm with a 79 cm warm bore for installation of the generator rotor assembly. This large, intrinsically stable coil was designed to achieve a uniform magnetic field in the area of the rotor brushes. The coil was wound with 87.5 km of copper-stabilized niobium/titanium superconductor in an epoxy matrix. Fabrication of the coil and its containment cryostat is complete, and it is being used in the high-voltage homopolar generator test program.

Development work for the Japanese LCT coil and its design and construction

This Paper describes the design, verification tests, and construction of the Japanese test coil for the Large Coil Task (LCT) under the auspices of IEA. The Japanese LCT coil was designed to be a pool-cooled, Nb-Ti, fully-stabilized coil with an operating current of 10 220 A at 8 T. Through research and development of the Japanese LCT coil, new advances in superconducting coil technology were acquired, such as mechanically and chemically treated conductor surfaces that have high heat transfer (about four times greater than usual). During the construction of the coil, new fabrication techniques were developed to wind the large-current conductor into a mechanically rigid coil and to construct a totally stable large coil. These advantages made it possible to construct the Japanese LCT coil which was completed in the spring of 1982.

日本のＬＣＴコイルの開発作業と設計・製作

This paper describes design, verification tests, and construction of the Japanese test coil for the Large Coil Task (LCT). Japan Atomic Energy Research Institute (JAERI) signed on the LCT international agreement under the International Energy Agency (IEA) in 1978, and since then JAERI has been working to develop the Japanese LCT coil to explore the problems of design and construction of tokamak toroidal coil. Based on the common requirements of the LCT, the Japanese LCT coil was designed to be a pool-cooled NbTi fully-stabilized coil whose operating current is 10, 220A at 8T.Through research and development of the Japanese LCT coil, new advances in the superconducting coil technology were obtained, such as mechanically and chemically treated conductor surface that has high heat transfer about four times as much as usual ones, nitrogen-strengthened stainless steel that has the yield strength twice as much as usual stainless steel, NbTi filaments those have the critical current density twice as much as those before LCT, and so on. These advances have enabled to construct the Japanese LCT coil and it was completed in the spring of 1982. During the construction of the coil, new fabrication techniques were obtained to wind large current conductor into a mechanically rigid coil and thus to construct a totally stable large coil.

Superconducting spin tipping solenoids for ZGS polarized beam facility

Two superconducting solenoids have been designed and built for the Argonne Zero Gradient Synchrotron (ZGS) Polarized Proton Beam Facility. Each solenoid will have a central field of 8.0 T, an effective field length of about 1.75 m, and a cold clear bore of 11.5 cm. It will generate a spin-tipping integral field of about 14 T-m. The integral field homogeneity over the cold bore is ± 4%. The magnet stored energy is about 0.7 MJ. Described in detail is the stability simulation on a high current density intrinsic stable coil. Comparisons are made between the simulation data and data obtained from the magnet performance tests. The cryostat design and construction are also presented.

Electroplated stabilized multifilament superconductor

This paper describes a method of manufacturing stabilized multifilament superconductors by connection of single or multifilament wires together by electroplating process. The method was tried first in summer 1965 just after appearing of paper by Kantrowitz and Stekly [1]. The scheme of the method is shown in Fig. 1. A set of parallel wires was wound onto a drum and then immersed into an electrolitic bath. The turns were separated with an insulated wire to prevent their coalescence. Copper covering of both sides of the set resulted in a high quality stable conductor. At that time we considered the method as a successful palliative which allowed us, however, to test our first stable coil in summer 1965 (Fig. 2). But eventually the advantages of the method became evident. Some of them are inherent to all compound conductors, i.e. conductors which consist of a number of smaller cross section conductors or wires joined in parallel. The advantages are as following: 1. The superconducting components can be manufactured by optimum process. They can be tested preliminary and properly selected. It eliminates the risk of spoiling great quantity of expensive superconducting alloy at once. 2. The length of the conductor is not determined by the size of a metallurgical billet. It is possible to make large cross section conductors of any necessary length without using of expensive metallurgical equipment. 3. Superconducting wires can be fully transposed in such a conductor.